CN104577701A - Erbium and ytterbium co-doped phosphate crystal laser device with wave bands of 1.55 micrometers - Google Patents

Abstract

The invention discloses an erbium and ytterbium co-doped phosphate crystal laser device with wave bands of 1.55 micrometers, and belongs to the field of solid laser materials and devices. The erbium and ytterbium co-doped phosphate crystal laser device has the advantages that the merits of high heat performance of phosphate crystals are utilized, erbium and ytterbium co-doped phosphate laser crystals are used as gain media, the doped concentration of erbium and ytterbium ions in the phosphate crystals are optimized, and accordingly high-performance solid laser light with the wave bands of 1.55 micrometers can be outputted by the aid of semiconductor laser pumping in wave bands of about 976 nanometers.

Description

Erbium-ytterbium double-doped phosphate crystal laser in 1.55 micron band

technical field

The invention relates to the field of solid laser materials and devices.

Background technique

Erbium-ytterbium co-doped phosphate glass is considered to be the most efficient 1.55 μm laser gain medium, and has been extensively researched and commercialized. The laser energy level fluorescence lifetime of Er ³⁺ in ⁴ I _13/2 in phosphate glass is as long as (6-8) ms, and the energy storage capacity is strong. Some Q-switched pulsed lasers have also been developed using this material as a gain medium at home and abroad. It is used in laser ranging, lidar and remote sensing and other fields. However, the low thermal conductivity (~0.8Wm ^-1 K ^-1 ) and laser damage threshold of phosphate glass make it difficult to achieve high average power output. Therefore, it is impossible to achieve high Energy and high repetition rate 1.55μm band Q-switched pulsed laser operation.

Phosphate crystal has an effective phonon energy (about 1200cm ^-1 ) very similar to that of phosphate glass; therefore, the spectral characteristics such as the fluorescence lifetime of Er ³⁺ ions in phosphate crystal are very close to those in phosphate glass. Co-doped phosphate crystals are expected to achieve the same efficient 1.55 μm laser operation as erbium-ytterbium co-doped phosphate glasses. In addition, crystals generally have higher thermal conductivity, mechanical properties, and laser damage thresholds than glasses. Therefore, using erbium-ytterbium double-doped phosphate crystal as the gain medium can realize higher performance 1.55μm band CW and Q-switched pulsed laser operation.

Contents of the invention

The object of the present invention is to use erbium-ytterbium double-doped phosphate laser crystal as gain medium, and obtain high-efficiency and high-average output power 1.55 μm band solid-state laser by optimizing the doping concentration of erbium and ytterbium ions in the crystal.

The present invention includes following technical solutions:

1. A 1.55 μm band solid-state laser is composed of a semiconductor laser pumping system, a laser resonator and a laser gain medium. It is characterized in that: the laser gain medium of the laser is Er _x Yb _y R _(1-xy) M(PO ₃ ) ₄ or Er _x Yb _y R _(1-xy) Me ₃ (PO ₄ ) ₃ or Er _x Yb _y R _(1-xy) M ₃ (PO ₄ ) ₂ or Er _x Yb _y R _(1-xy) MP ₂ O ₇ or Er _x Yb _y R _(1-xy) P ₅ O ₁₄ or Er _x Yb _y R _{( 1-xy)} PO ₄ crystal, wherein x=0.3～3.0at.%, y=5～50at.%, R is a certain element or a combination of several elements among Sc, Y, Gd, Lu, M is Li, A certain element or a combination of several elements in Na and K elements, Me is a certain element or a combination of several elements in Mg, Ca, Sr, and Ba elements; the semiconductor laser pumping system includes a 976nm wavelength semiconductor laser and placed on the semiconductor laser and An optical coupler between laser gain media; the laser resonator is composed of input and output mirrors; the input mirror is designed to have a transmittance T≥70% near the wavelength of 976nm, and a transmittance T≤1% at the 1.55μm band; the output The mirror is designed to have a transmittance of 0.5%≤T≤10% at the 1.55μm wavelength band.

2. The solid-state laser as described in item 1. It is characterized in that the input and output mirrors are respectively directly plated on one or two opposite end faces of the laser gain medium.

3. A 1.55 μm band solid-state pulsed laser. It is characterized in that: a Q-switching or mode-locking element in the 1.55 μm band is inserted between the laser gain medium and the output mirror of the laser described in item 1; the Q-switching or mode-locking element can also be placed in the laser resonator at the same time.

4. The solid-state laser as described in item 3. It is characterized in that: the input mirror is directly plated on the input end surface of the laser gain medium; the output mirror can also be directly plated on the output end surface of the Q-switching or mode-locking element.

5. A tunable solid-state laser in the 1.55 μm band. It is characterized in that a wavelength tuning element in the 1.55 μm band is inserted between the laser gain medium and the output mirror of the laser described in Item 1.

6. A frequency-doubled laser in the 1.55 μm band. It is characterized in that: a frequency doubling crystal in the 1.55 μm band is inserted between the laser gain medium and the output mirror of the laser described in Item 1, and the output mirror of the laser resonator is designed to have a transmittance of less than 0.5% at the 1.55 μm band. The transmittance at the frequency band of 775nm is greater than 80%; the output mirror can also be directly plated on the output end surface of the frequency doubling crystal.

7. A 1.55 μm band frequency doubled pulse laser. It is characterized in that a Q-switching or mode-locking element in the 1.55 μm band is inserted between the laser gain medium and the frequency doubling crystal of the laser described in Item 6.

The beneficial effect of the solid-state laser manufactured by utilizing the technical solution of the present invention is that it can obtain high output power and high efficiency continuous and high pulse energy, high repetition frequency and narrow pulse width Q-switched pulse 1.55 μm band solid-state laser, and the device is compact and stable Reliable and easy to use.

Detailed ways

Example 1: 976nm semiconductor laser end-pumped Er:Yb:KGd(PO ₃ ) ₄ crystal to achieve 1.55μm solid-state laser output.

A KGd(PO ₃ ) ₄ laser crystal doped with 1.5 at.% Er ³⁺ and 30 at.% Yb ³⁺ was grown by molten salt method. Polish the end face of the laser crystal with a thickness of 1.0 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, the transmittance of T=0.1% at the wavelength of 1.55 μm, and the transmittance of the output mirror of the laser cavity is T=1.5% at the wavelength of 1.55 μm. A 1.55μm solid-state laser output with a continuous power higher than 1.5W can be obtained by using a 20W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 2: 976nm semiconductor laser end-pumped Er:Yb:KGd(PO ₃ ) ₄ crystal to achieve 1.55μm solid-state pulsed laser output.

Directly insert the passive Q-switching sheet (such as Co ²⁺ : MgAl ₂ O ₄ , Co ²⁺ : ZnSe, Cr ²⁺ : ZnSe, etc.) or the acousto-optic Q-switching module of 1.55 μm band into the laser crystal and the output mirror in Example 1. 1.55μm Q-switched pulsed laser operation can be realized. The output mirror can also be directly plated on the output end surface of the passive Q-switching chip or the acousto-optic Q-switching module to achieve the same purpose.

Example 3: 976nm semiconductor laser end-pumped Er:Yb:KGd(PO ₃ ) ₄ crystal to realize 1510-1600nm tunable solid-state laser output.

Directly insert the wavelength tuning element (birefringence filter, grating or prism, etc.) in the 1.55μm band between the laser crystal and the output mirror of the laser cavity in Example 1, and use the 976nm semiconductor laser end pump to achieve 1510-1600nm. Tune the laser output.

Example 4: 976nm semiconductor laser end-pumped Er:Yb:KGd(PO ₃ ) ₄ crystal to realize 775nm frequency doubled solid-state laser output.

Directly insert a nonlinear optical crystal (such as KTP, LBO, β-BBO, etc.) with a frequency doubled wavelength of 1.55 μm between the laser crystal and the output mirror in Example 1, and coat the output mirror with a high reflection at a wavelength of 1.55 μm (T≤ 0.5%), a high-transmittance (T≥80%) dielectric film at a frequency-doubled wavelength of 775nm, can realize 775nm frequency-doubled laser. The output mirror can also be directly plated on the output end surface of the nonlinear optical crystal to achieve the same purpose.

Example 5: 976nm semiconductor laser end-pumped Er:Yb:Ca ₃ Gd(PO ₄ ) ₃ crystal to achieve 1.6μm solid-state laser output.

Ca ₃ Gd(PO ₄ ) ₃ laser crystals doped with 2.0 at.% Er ³⁺ and 30 at.% Yb ³⁺ were grown by molten salt method. Polish the end face of the laser crystal with a thickness of 2.0 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976 nm, the transmittance of T=0.1% at the wavelength of 1.6 μm, and the transmittance of the output mirror of the laser cavity is T=1.0% at the wavelength of 1.6 μm. A 1.6μm solid-state laser output with a continuous power higher than 1.0W can be obtained by using a 20W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 6: A 976nm semiconductor laser end-pumps Er:Yb:Na ₃ Gd(PO ₄ ) ₂ crystals to achieve 1.6 μm solid-state laser output.

Na ₃ Gd(PO ₄ ) ₂ laser crystal doped with 1.0 at.% Er ³⁺ and 20 at.% Yb ³⁺ was grown by molten salt method. Polish the end face of the laser crystal with a thickness of 1.5 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976 nm, the transmittance of T=0.1% at the wavelength of 1.6 μm, and the transmittance of the output mirror of the laser cavity is T=1.0% at the wavelength of 1.6 μm. A 1.6μm solid-state laser output with a continuous power higher than 1.0W can be obtained by using a 20W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 7: 976nm semiconductor laser end-pumped Er:Yb:NaLuP ₂ O ₇ crystal to achieve 1.55μm solid-state laser output.

NaLuP ₂ O ₇ laser crystal doped with 0.8 at.% Er ³⁺ and 15 at.% Yb ³⁺ was grown by molten salt method. Polish the end face of the laser crystal with a thickness of 1.5 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, the transmittance of T=0.1% at the wavelength of 1.55 μm, and the transmittance of the output mirror of the laser cavity is T=2.0% at the wavelength of 1.55 μm. A 1.55μm solid-state laser output with a continuous power higher than 1.0W can be obtained by using a 20W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 8: 976nm semiconductor laser end-pumped Er:Yb:YP ₅ O ₁₄ crystal to achieve 1.54μm solid-state laser output.

The YP ₅ O ₁₄ laser crystal doped with 1.3at.% Er ³⁺ and 25at.% Yb ³⁺ was grown by molten salt method. Polish the end face of the laser crystal with a thickness of 1.0 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, the transmittance of T=0.1% at the wavelength of 1.54 μm, and the transmittance of the output mirror of the laser cavity is T=2.0% at the wavelength of 1.54 μm. A 1.54μm solid-state laser output with a continuous power higher than 1.0W can be obtained by using a 20W 976nm semiconductor laser end pump. It is also possible to plate the laser cavity input and output mirrors on the two end faces of the laser crystal respectively to achieve the same purpose

Example 9: 976nm semiconductor laser end-pumped Er:Yb:LuPO ₄ crystal to achieve 1.54μm solid-state laser output.

LuPO ₄ laser crystal doped with 0.6at.% Er ³⁺ and 15at.% Yb ³⁺ was grown by molten salt method. Polish the end face of the laser crystal with a thickness of 0.3 mm (the end area is generally square millimeters to square centimeters), fix it on a copper seat with a light hole in the middle, and place it in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976 nm, the transmittance of T=0.1% at the wavelength of 1.54 μm, and the transmittance of the output mirror of the laser cavity is T=1.5% at the wavelength of 1.54 μm. A 1.54μm solid-state laser output with a continuous power higher than 1.5W can be obtained by using a 20W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Claims (7)

1. 1.55 mu m waveband solid state lasers, are made up of semiconductor laser pumping system, laserresonator and gain medium, it is characterized in that: the gain medium of this laser is Er _xyb _yr _(1-x-y)m (PO ₃) ₄or Er _xyb _yr _(1-x-y)me ₃(PO ₄) ₃or Er _xyb _yr _(1-x-y)m ₃(PO ₄) ₂or Er _xyb _yr _(1-x-y)mP ₂o ₇or Er _xyb _yr _(1-x-y)p ₅o ₁₄or Er _xyb _yr _(1-x-y)pO ₄crystal, wherein x=0.3 ~ 3.0at.%, y=5 ~ 50at.%, R is the combination of a certain element or some elements in Sc, Y, Gd, Lu element, M is the combination of a certain element or some elements in Li, Na, K element, and Me is the combination of a certain element or some elements in Mg, Ca, Sr, Ba element; The optical coupler that semiconductor laser pumping system comprises 976nm wavelength semiconductor laser and is placed between semiconductor laser and gain medium; Laserresonator is made up of input and output mirror; Input mirror is designed to transmitance T>=70% near 976nm wavelength, at 1.55 mu m waveband place transmitance T≤1%; Outgoing mirror is designed at 1.55 mu m waveband place transmitance 0.5%≤T≤10%.

2. solid state laser as claimed in claim 1, is characterized in that: by input and output mirror difference direct plating on one or two opposing end surface of described gain medium.

3. 1.55 mu m waveband solid pulse lasers, is characterized in that: between the gain medium and outgoing mirror of laser according to claim 1, insert 1.55 mu m wavebands tune Q or locked mode element; Also tune Q or locked mode element can be placed in laserresonator simultaneously.

4. solid state laser as according to claim 3 in item, is characterized in that: by input mirror direct plating on the input end face of described gain medium; Also can by outgoing mirror direct plating on the output end face of described tune Q or locked mode element.

5. 1.55 mu m waveband tunable solid lasers, is characterized in that: the wavelength tuning element inserting 1.55 mu m wavebands between the gain medium and outgoing mirror of laser according to claim 1.

6. a mu m waveband frequency double laser, it is characterized in that: the frequency-doubling crystal inserting 1.55 mu m wavebands between the gain medium and outgoing mirror of laser according to claim 1, laserresonator outgoing mirror is designed to be less than 0.5% in 1.55 mu m waveband place transmitances, and at frequency-doubled wavelength 775nm wave band place, transmitance is greater than 80%; Also can by outgoing mirror direct plating on the output end face of described frequency-doubling crystal.

7. 1.55 mu m waveband frequency doubling pulse lasers, is characterized in that: between the gain medium and frequency-doubling crystal of laser according to claim 6, insert 1.55 mu m wavebands tune Q or locked mode element.